Blood treatment apparatus and similar medical devices comprise an extracorporeal circuit provided with at least one blood treatment or blood processing unit, one tube, connecting a blood removal zone to said unit, and a second tube, extending downstream of the treatment or processing unit towards a blood return zone to the patient or towards a blood/blood components collection zone. Blood is moved from the patient or donor to the treatment or processing unit via pumps or other actuators controlled by the machine.
In case the machine is for instance a hemodialysis apparatus, then for achieving the required treatment of blood, an adequately prepared dialysis liquid shall be sent to the treatment unit, and water removal through the treatment unit membrane as well other machine parameters shall be controlled. Depending upon the type of hemodialysis machine and upon the type of treatment, a user can have the possibility to set a number of parameters in order to impose a specific prescription to a patient, such as for instance: flow rates of the various liquids, temperatures and conductivity of the liquids, concentration of the liquids used during treatment, flow rates of any anticoagulants used and delivered during treatment, pressures in the fluid conduits, net liquid removal rates of plasma water from whole blood and so on.
It is therefore evident that users (the patient himself, a physician, a nurse) have normally a plurality of parameters to set before or even during the process performed by the medical apparatus.
Particularly important parameter are those that can take variable values or profiles through the treatment, referring to extracorporeal blood treatment these parameters can be ultrafiltration, conductivity of the dialysis liquid, concentration of a specific substance in the dialysis liquid, flow rate of an infusion or substitution solution, temperature of the dialysis liquid, temperature of blood, temperature of an infusion solution, concentration of a certain specific drug that is delivered to the patient, etcetera.
In this situation it is important that machines as blood treatment machines or blood processing apparatus where the process executed by the machine acts on a patient's or donor's blood, the user interface is designed to allow easy and safe data entry.
Particularly, in case of treatment of patients suffering from kidney failure, the patient is constantly connected to the machine with the serious risk that any failure in entering or in actuating a prescription could have negative impacts on the treatment delivery and on patient's health.
In this situation several technical solutions have been developed in the past in order to render parameters values data entry in blood treatment or blood processing apparatus relatively easy and reliable.
A data entry user interlace of general purpose and not specifically designed for the medical field is known from U.S. Pat. No. 5,546,582.
A first known method for entering data in a dialysis machine is described in U.S. Pat. No. 5,247,434. This method comprises the following steps:
(a) providing a touch screen interlace with an indicium thereon corresponding to a treatment parameter;
(b) touching the indicium;
(c) in response to said touching, invoking a data entry pad on a region of the touch screen,
(d) entering a parametric value corresponding to the treatment parameter by touching one or more buttons of the data entry pad;
(e) touching a first region of the data entry pad to signal entry of the parametric value;
(f) displaying on the touch screen a button soliciting verification of the newly entered parametric value;
(g) touching the button soliciting verification; and
(h) in response to steps (b)-(g), causing the parametric value corresponding to the treatment parameter to be changed.
In other words before really implementing a change a user is solicited to verify the newly entered parameter and to press a button confirming the change.
The same patent also discloses a method for entering variable parameters, i.e. parameters that can vary in the course of time during treatment.
More in detail U.S. Pat. No. 5,247,434 shows a method of programming a time-varying parameter comprising the steps:
(a) providing a touch screen interface;
(b) displaying on the touch screen first and second axes, the first axis corresponding to the time-varying parameter, the second axis corresponding to time;
(c) touching the touch screen at a plurality of points to define points on a parameter-versus-time curve;
(d) presenting on the touch screen a series of bars corresponding to said curve;
(e) selecting one of said bars for alteration;
(f) displaying on the screen a numeric parameter corresponding to the selected bar;
(g) touching the screen at first or second locations to increase or decrease, respectively, the displayed numeric parameter and thereby alter the value of the numeric parameter to which the selected bar corresponds.
(h) touching the screen at a third location to signify completion of steps (b)-(g), and
(i) storing data corresponding to the bars in a memory to which the process-control system can refer in changing the time-varying parameter with time.
Document U.S. Pat. No. 5,326,476 teaches a further method for entering a time variable parameter, ultrafiltration in particular, in a hemodialysis machine, having a programmable memory and having ultrafiltration capability, so as to enable the machine to perform ultrafiltration of fluid from a patient according to a time-variable ultrafiltration profile. The method disclosed in U.S. Pat. No. 5,326,476 comprises the following steps:
(a) entering into the programmable memory a prescribed time for dialysis;
(b) entering into the programmable memory a target ultrafiltration volume of fluid to be removed from the patient;
(c) entering into the programmable memory a proposed ultrafiltration profile being representable as a plot of coordinates on an ultrafiltration rate axis and a time axis and defining a profile ultrafiltration volume; and
(d) shifting the proposed ultrafiltration profile along the ultrafiltration rate axis to the degree necessary to make the profile ultrafiltration volume equal to the target ultrafiltration volume, so as to allow the hemodialysis machine to achieve, while ultrafiltrating the fluid according to the shifted ultrafiltration profile, the entered target ultrafiltration volume within the entered prescribed time.
This method allows the user to enter a profile curve and to move the ultrafiltration profile along the ordinates so as to achieve the desired integral value in the desired time frame.
A further user interface system for a dialysis machine is known from document U.S. Pat. No. 5,788,851. This user interface does not specifically relate to data entry of profiles and comprises, in summary, the following features:                a touch screen displaying messages and information and permitting to select a parametric value pertinent to operation of said machine or pertinent to a treatment by said machine,        one hard key off of said touch screen, said touch screen prompting a user to press said hard key to signify that the selection of the parametric value has been completed;        a control system having a host and a safety processing unit, wherein pressing of said hard key causes transfer of information relating to the selected parametric value from the host processing unit to the safety processing unit which is then checking said selected parametric value to confirm that said parametric value meets validation or safety criteria for a patient connected to said machine.        
A further known technique is described in U.S. Pat. No. 6,830,693, which relates to a method of setting up a dialysis treatment in a dialysis machine comprising the steps of: determining conditions of a dialysis treatment adapted to a specific patient, determining a first function (U(t)) of a first quantity (U) characterizing the dialysis treatment as a function of time (t) the first function (U(t)) satisfying said conditions of the dialysis treatment and corresponding to a curve having a defined shape; and determining a second function (C(t)) of a second quantity (C) characterizing the dialysis treatment, the’ second function (C(t)) being correlated with the first function (U(t)) by constants (M, N) determined experimentally and the second function (C(t)) corresponding to a curve having a shape of the same kind as the shape of the first curve.
Finally, U.S. Pat. No. 6,881,344 relates to a user interface and to a method of setting up a dialysis treatment in a dialysis machine wherein a group of parametric functions (U(t, P); C(t, P)) representing ultrafiltration or conductivity as a function of time (t) and of a parameter (P) are provided. By imposing boundary conditions that are characteristic of a particular therapy and assigning values to the parameter (P) the user selects the curve and the machine calculates and displays the curves corresponding to the user's selection; the user can then confirm selection on the basis of the images of the curves.